import sys
# from PyQt5 import QtWidgets, QtCore
from PyQt5 import QtWidgets


class MyMainClass():
    def __init__(self):
        pass


if __name__ == "__main__":

    app = QtWidgets.QApplication(sys.argv)
    widget = QtWidgets.QWidget()
    widget.resize(400, 400)
    widget.setWindowTitle('Hello World')
    widget.show()
    sys.exit(app.exec())
